Four different strains of yeast are used: for Contrapils, for Tonneke and Contreras’ Especial Mars, for Valeir blond, Valeir donker and Extra, and for Valeir divers.

Milling the malt

One day before the brewing, the two brew kettles (respectively with a capacity of 37 and 66 hl) are filled with brewing water and then heated. At the same time, the malt is milled and placed in bags above the filtration tank. In this way, everything will be ready to start on Thursday at 5AM.

Malt deposit and preparation of the wort

First, the mash (a mixture of warm water and malt) is made in the mash and filtration tank. At regular intervals boiling water is added so that the temperature of the water-malt mixture rises continuously, up to final temperature of 72° C, stopping all enzymatic activity.

Adding of the hops and boiling of the wort

Through gooseneck faucets the filtrate runs into a bottom tank, where the wort is transferred to the largest brew kettle (66 hl). The spent grain that remains is once again mixed with boiling water from the second brew kettle. This filtrate then returns to the small brew kettle (37 hl). After one and a half hours of boiling, the hops are mixed with the boiling wort, after which the mixture is cooled.

Cooling the wort and adding the yeast

From this bottom tank, the boiled wort is pumped to the resting tank on the first floor, and subsequently to the Baudelot cooler. This cooler cools the wort to 22° C (top fermentation) or 14° C (bottom fermentation), while the wort is also aerated. Yeast is then added to the cooled wort.

The Fermentation Process

Primary fermentation

The cooled wort with the added yeast runs gravitationally to the main fermentation hall. Here, the young beer ferments in a closed tank. After approximately one week (for lager at 14° C) or three to four days (for top fermentation at 22° C) the beer is cooled to respectively 5° C and 15° C, after which it is moved to horizontal lagering tanks in the basements.

Lagering

In the basements the beer undergoes lagering at 2° C. Following a resting period of 4 weeks for top fermentation beers and 6 weeks for bottom fermentation beers, fermentation stops.

Filtration and filling

After lagering the beer passes the yeast separator and the plate filter to the bright beer tanks. Here, beers without secondary fermentation are saturated, while yeast is added for a second time to beers with secondary fermentation in bottle or keg.